1. Field of the Invention
The present invention is directed to lighting fixtures. More particularly, the present invention is directed to a low voltage lighting fixture having track electrodes.
2. The Prior Art
Prior art lighting fixtures are typically of either standard incandescent lights or fluorescent lights. Ordinary incandescent lights, which use tungsten filaments, produce a great deal of heat relative to the amount of light they produce, which must be dissipated to prevent fire hazard. In many lighting applications, especially in retail display, incandescent lights would overheat if placed in the location that provides the best lighting, causing them to burn out prematurely or to create a fire hazard because the best location does not allow ready heat dissipation.
A common example of such a situation is the enclosed glass retail display case with lights along the inside of the top surface. The top of the display case naturally traps much of the heat generated by the lights. Ordinary incandescent lights cannot customarily be used in such display cases. Window displays are also often enclosed by partitions that create small enclosed spaces. These can often be lighted with ordinary incandescent lights only by using spotlights that are placed some distance away from the displayed goods themselves, in order to provide sufficient heat dissipation. When the light bulbs are placed some distance from the display, naturally the lighting tends to be flat and washed out and does not provide as much contrast and shadow, which add drama and appeal to a display, and, in the retail trade, increase sales.
In addition, the color temperature of ordinary incandescent lights is about 2,400 to 2,600 degrees Kelvin. Consequently, the colors of objects viewed under light from these bulbs are distorted, and are generally less attractive than they appear in sunlight.
Furthermore, incandescent lights produce light very inefficiently relative to other types of electric lamps, such as fluorescent lights, producing much waste heat from the wasted electricity. And the life expectancy of an ordinary incandescent light is very short, usually only about 750 hours to 1,000 hours. The only practical way to extend this life is to reduce the operating voltage of the light, which reduces both the light output and the color temperature of the light to a degree that most people will not accept.
Finally, when there are lighting applications suitable for ordinary incandescent lights, the heat dissipation requirements often also limit the selection of locations and positions that the lamps can be put in. This reduces the flexibility of the lighting system to be changed when the subject matter of the lighting is changed, as for example, window displays are frequently changed. The resulting lighting is substantially permanent, and difficult to change. It is certainly not portable. Aside from physical limitations naturally presented by the bulky physical apparatus, such lighting is nearly always operated by at least 120 volt alternating electric current, which Underwriters Laboratories classifies as permanent lighting installation. This classification leads to many electrical and heat dissipation requirements that greatly limit the arrangements that can be made with such lights.
To overcome these disadvantages of incandescent lights, fluorescent lights are often used in offices, retail displays, and so forth. Fluorescent lights, however, have several disadvantages that seriously limit their attractiveness. They produce a constant flicker that irritates many people and can cause headaches. They produce low intensity flat lighting, which does not make displays attractive. Moreover the spectrum of most fluorescent lights is heavily weighted in the yellow-green portion of the spectrum, producing an unpleasant distortion of all colors. In addition, fluorescent lights are bulky. Finally, they too are classified as permanent lighting installations by Underwriters Laboratories, triggering many restrictions on their connections and placements.
In many applications, especially displays of merchandise or art, the objects to be lighted are frequently changed or rearranged. When a display is changed, it is desirable to change the lighting of the display to enhance the attractiveness and clarity of the display. It is often difficult or impractical to change the lighting because the use of permanent lighting carries so many restrictions on placement and heat dissipation, and the fixtures and related equipment are essentially permanent by their nature and so are difficult to move. In the case of many incandescent lights and virtually all fluorescent lights, the light from the lamps cannot even be redirected.
In many display applications, merchandise or other items are displayed by hanging the items from slatwall, which is a generally wooden panel-like wall board having parallel longitudinal slots cut into it. Slatwall displays are customarily lighted in the manners described above. The difficulties associated with conventional display lighting, however, are exacerbated when the display is mounted on a slatwall. Items displayed on slatwalls are often in display windows, making the display items farther from ceiling lights or other permanent lights. In addition, items displayed on slatwalls are often relatively small items, such as shoes, handbags, stuffed animals, cameras, and so forth. Items like these are most effectively displayed when each item or group of items is individually lighted with a strong bright light. Finally, the displays on slatwalls are more likely to be changed frequently than are other types of displays because they are relatively easy to change and because they are often used for fashion merchandise.
Therefore a need exists for a lighting system that is portable under the definitions of the Underwriters Laboratory and many local building codes, that includes lights that can be readily repositioned and redirected to any desired direction at any time with a minimum of effort, that have a high color temperature to enhance the natural colors of objects, that can be placed near to the objects to be lighted, and that can be placed without regard for the need to dissipate heat and that is specifically adapted for use with existing slatwall display installations.